import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;

public class HashSetTest {

	public static void main(String[] args) {
		
		Set set = new HashSet();
		set.add(1);
		set.add(1);
		set.add(3);
		for (Iterator iterator = set.iterator(); iterator.hasNext();) {
			Integer num = (Integer) iterator.next();
			System.out.println(num);
		}
		
	}
	
}
